In the existing chained flashlight systems used in Japanese airports, for example, 29 flashlights (hereinafter also referred to as “lamps”) are repeatedly activated sequentially from one end of a runway to the other end at about 17 milliseconds per one lamp (0.5 seconds per one cycle), and a lighting signal is directly sent from the traffic controller (traffic control device) to each lamp. Therefore, many communication wires are used between the controller and each lamp (Patent Literatures 1 and 2).